JP2001330050A - Tripod type constant velocity universal joint - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the vibration of a tripod type constant velocity universal joint by regulating a skew of a needle roller 32 assembled between a trunnion and journal 22 and a roller 30. SOLUTION: Angle of skew of the needle roller 32 is regulated within the predetermined regulation value. Desirably, the angle θ1 of skew of the needle roller 32 to be generated by a circumferential clearance is formed larger than the angle θ2 f skew of the needle roller 32 to be generated by a radial clearance in an annular space between the roller and the trunnion and the journal 22, and the angle θ2 of the later is set within a range at 4.0-4.5 degree.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sliding tripod type constant velocity universal joint used for power transmission in automobiles and industrial machines.

[0002]

2. Description of the Related Art As shown in the left half of FIG. 6, a tripod type constant velocity universal joint comprises an outer joint member 1 having a track groove 12 'extending in the axial direction at an inner circumferential position equally divided into three equal parts.
0 ′, a tripod member 20 ′ comprising a trunnion body 21 fitted to the shaft so as to transmit torque and a trunnion journal 22 ′ protruding radially from a circumferentially equally divided position of the trunnion body 21. A roller 30 'rotatable around each trunnion journal 22' via a plurality of needle rollers 32 'and housed in the track groove 12', the roller 30 'being provided on its outer peripheral surface with the track groove 12'. Are guided by roller guide surfaces 14 'formed on both side walls of the roller.

In a conventional tripod type constant velocity universal joint, a trunnion journal 22 ', a needle roller 32',
The clearance between the rollers 30 (radial clearance, circumferential clearance) has not been set in consideration of the skew angle. Here, the skew of the roller means that the axis of the roller is inclined at a small angle (θ) without forming a correct right angle in the traveling direction, as shown in FIG.

[0004]

It has been found that the NVH characteristics of a tripod type constant velocity universal joint change depending on the angle at which the needle rollers can actually skew. The skew angle is determined from the radial clearance and the circumferential clearance,
Heretofore, this has not been taken into account. For this reason, the NVH characteristics differ depending on the proportion and size of the tripod type constant velocity universal joint, and optimization has not been achieved at present.

An object of the present invention is to reduce the vibration of a tripod type constant velocity universal joint by suppressing the skew of a needle roller.

[0006]

The angle at which the needle rollers can actually skew, that is, the degree of freedom of the skew angle, is limited by the diameter clearance (radial clearance) and the clearance between the rollers in the pitch circle (circumferential clearance). Subject to the restrictions
The smaller of the two will be dominant. In the case of skew due to circumferential clearance, skew can occur until the rollers come into contact with each other.
Is represented by

[0007]

(Equation 1)

Where D is the inner diameter of the roller, d is the roller diameter,
Z is the number of rollers.

In the case of skew due to radial clearance, skew can occur until both ends of the roller come into contact with the inner diameter of the roller, and the skew angle θ2 at this time is expressed by Equation 2.

[0010]

(Equation 2)

Here, gr is the radial clearance, and l is the effective length of the roller.

The skew angles θ1 and θ2 are obtained, and the smaller one is the skew angle that can actually occur (see: Noriyoshi Soda, “Bearing” published by Iwanami Shoten).

The relationship between the skew angles θ1 and θ2 is θ1> θ2, and the skew angle θ2 is between 4.0 ° and 4.0 °.
When the radial clearance was set to be 5 °, it was found that the vibrating force of the tripod type constant velocity universal joint exhibited a minimum value. By taking this into consideration, it is possible to optimize the tripod type constant velocity universal joint with respect to lowering the vibration.

According to a first aspect of the present invention, there is provided an outer joint member having a track groove extending in the axial direction at an inner circumferential position divided into three equal parts in the circumferential direction, a trunnion body fitted to the shaft so as to transmit torque, and the trunnion. A tripod member consisting of a trunnion journal protruding radially from a circumferential trisection of the trunk, and rotatably attached to each trunnion journal via a plurality of needle rollers and housed in the track groove And a skew angle of the needle roller in a tripod-type constant velocity universal joint in which the roller is guided by roller guide surfaces formed on both side walls of the track groove on the outer peripheral surface thereof. Is regulated within a predetermined standard value.

According to a second aspect of the present invention, in the tripod type constant velocity universal joint according to the first aspect, a needle generated by a radial clearance of the needle roller in an annular space between the roller and the trunnion journal. The skew angle (θ2) of the roller is regulated within a predetermined standard value. The skew angle (θ2) is calculated based on the above equation (2), based on the roller inner diameter D, the radial clearance gr, and the effective length l of the needle rollers.
Can be determined by appropriately combining the above values.

Specifically, the preferable range of the skew angle (θ2) is from 4.0 ° to 4.5 as in the third aspect of the present invention.
° range. This means that the skew angle (θ2) is 4.0
This is because it has been found that the thrust force is minimized in the range of ° to 4.5 °. Skew angle (θ2) is 4.5
When the angle exceeds 0 °, the thrust force increases and saturates at a certain level. Conversely, when the skew angle (θ2) becomes smaller than 4.0, the thrust force tends to increase.

According to a fourth aspect of the present invention, in the tripod type constant velocity universal joint according to any one of the first to third aspects, the skew angle (θ1) of the needle roller which can be generated by the circumferential clearance is smaller than that of the roller. The skew angle (θ2) of the needle roller which may be caused by a radial clearance in the annular space between the trunnion journal and the trunnion journal is larger than the skew angle (θ2). As described above, the smaller of the skew angle (θ1) that can be generated by the circumferential clearance and the skew angle (θ2) that can be generated by the radial clearance is the skew angle that can actually occur. By reducing (θ2), it is possible to take measures against needle roller skew by regulating only this skew angle (θ2).

According to a fifth aspect of the present invention, in the tripod type constant velocity universal joint according to any one of the first to fourth aspects, the contact ratio between the roller and the roller guide surface is 1.02 to 1.02.
1.2, wherein the width dimension of the roller is so small that the contact ellipse generated on the roller does not deviate from the end face of the roller under a predetermined torque load. If the contact ratio is small, the contact ellipse becomes large under torque load and exceeds the width of the roller, resulting in a short life. Conversely, if the contact ratio is large, the contact ellipse becomes small, but the surface pressure increases and the contact area increases. Is promoted, and the life is shortened.

Further, reducing the width of the roller contributes to the downsizing of the outer joint member and, consequently, the overall tripod type constant velocity universal joint. More specifically, the width (Ls) of the roller and the outer diameter (d)
The value of the ratio (Ls / do) to o) is preferably set to 0.24 to 0.27. The smaller the value of this ratio (Ls / do), the smaller the width Ls of the outer diameter do of the roller, and thus the greater the degree of contributing to compactness. Therefore, the lower limit is determined from that aspect.

According to a seventh aspect of the present invention, in the tripod type constant velocity universal joint according to any one of the first to fifth aspects, the contact surface pressure generated between the roller and the roller guide surface and the trunnion journal are provided. The width dimension of the roller and the length of the needle roller are set such that the contact surface pressure generated between the roller and the needle roller is substantially equal.
This is because, by making the contact surface pressure uniform, one of them does not wear out early and deteriorate the durability of the entire tripod type constant velocity universal joint.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS.

First, the basic structure of a tripod type constant velocity universal joint will be described. As shown in FIGS. 1 and 2, a tripod type constant velocity universal joint is connected to one of two rotating shafts to be connected. The outer joint member 10 and a tripod unit (20, 30, 32) connected to the other rotating shaft are main components.

The outer joint member 10 has a hollow cup shape in which three track grooves 12 extending in the axial direction are arranged at equally spaced positions in the circumferential direction, and the inner periphery of the outer joint member 10 alternately appears in the circumferential direction. It is composed of a small inner diameter part and a large inner diameter part. Each track groove 12 forms a roller guide surface 14 on the opposite side wall. The roller guide surface 14 is a part of a cylindrical surface, that is, a partial cylindrical surface.

The tripod unit includes a tripod member 20, a roller 30, and a plurality of needle rollers 32.

The tripod member 20 has three trunnion journals 2 projecting radially at equally spaced positions in the circumferential direction.
2 Each trunnion journal 22 has a cylindrical outer peripheral surface 24 and an annular ring groove 26 formed near the shaft end. A roller 30 is rotatably fitted on the outer periphery of the trunnion journal 22 via a plurality of needle rollers 32. Cylindrical outer peripheral surface 2 of trunnion journal 22
4 provides the inner raceway surface of the needle roller 32. Roller 30
Has an inner peripheral surface which is cylindrical and provides an outer raceway surface for the needle rollers 32.

The needle roller 32 contacts the outer washer 34 at the outer end face of the tripod member 20 as viewed in the radial direction, and contacts the inner washer 38 at the opposite end face. Since the outer washer 34 is restricted from moving in the axial direction by the circlip 36 mounted in the ring groove 26, the needle roller 32 is also restricted from moving in the axial direction after all. The outer washer 34 includes a disk portion 34a extending in the radial direction of the trunnion journal 22 and a cylindrical portion 34b extending in the axial direction of the trunnion journal 34.
The cylindrical portion 34b of the outer washer 34 has an outer diameter smaller than the inner diameter of the roller 30, and expands to a diameter larger than the inner diameter of the roller 30 at an outer end 34c of the tripod member 20 as viewed in the radial direction. . Therefore, the roller 30 can move in the axial direction of the trunnion journal 22.

The outer peripheral surface of the roller 30 may be a partially spherical surface having a center of curvature on the axis, or may be a convex curved surface having a generatrix having a center of curvature at a position radially away from the axis. . Further, the roller guide surface 14 and the roller 30
May be an angular contact as shown in FIG. 4 (A) or a circular contact as shown in FIG. 4 (B). Since the angular contact has a certain contact angle and makes contact at two points, a contact ellipse occurs at two points in the contact angle direction. Circular contacts make contact at one point because they are spherical contacts. In any case, it is necessary to set the width W of the roller 30 so that when a predetermined torque is applied, the contact ellipse does not deviate from the end face of the roller 30 and falls within the roller width. If the contact ratio is small, the contact ellipse becomes large under the torque load and exceeds the width Ls of the roller 30, resulting in a short life. vice versa,
If the contact ratio is large, the contact ellipse is small, but the contact pressure is high and the wear of the contact portion is promoted, resulting in a short life. However, since the surface pressure of the tripod type constant velocity universal joint is most severe between the trunnion journal 22 and the needle roller 32 due to its structure, the contact ratio should be set so as not to exceed the surface pressure at this portion. I just need. Specifically, the contact ratio is 1.02
To 1.2, more preferably 1.05 to 1.18. The value of the ratio Ls / do between the width Ls of the roller 30 and the outer diameter do is set to 0.24 to 0.27.

Further, the contact surface pressure generated between the roller 30 and the roller guide surface 14 and the trunnion journal 22
It is preferable to set the width Ls of the roller 30 and the effective length 1 of the needle roller 32 so that the contact surface pressure generated between the roller 30 and the needle roller 36 is substantially equal.

In the above-described embodiment, the induced thrust was measured for a plurality of tripod type constant velocity universal joints in which only the skew angle θ2 of the needle roller 32 due to the radial clearance was changed, and the results as shown in FIG. 5 were obtained. was gotten. The test conditions are as follows. Torque: 294 Nm Operating angle: 7 deg Rotational speed: 150 rpm FIG. 5 plots the induced thrust force of the tripod-type constant velocity universal joint and the abscissa the calculated skew angle θ2 (deg), and plots the measured thrust force data. It was done. It can be seen from the figure that the thrust force shows the minimum value when the skew angle θ2 is in the range of 4.0 ° to 4.5 °. If the skew angle θ2 exceeds 4.5 °, the thrust force increases and saturates at a certain level. When the skew angle θ2 is smaller than 4.0, the thrust force tends to increase. Therefore, regarding the skew of the needle rollers 32,
By setting the skew angle θ2 in the range of 4.0 ° to 4.5 °, the induced thrust of the tripod type constant velocity universal joint can be reduced, and low vibration can be achieved.

[0030]

As described above, the outer joint member formed with the track groove extending in the axial direction at the circumferentially equal position of the inner circumference at three equally spaced positions, the trunnion body portion fitted to the shaft so as to transmit torque, and A tripod member consisting of a trunnion journal radially protruding from a circumferential trisection position of the trunnion body, and a rotatably mounted via a plurality of needle rollers to each of the trunnion journals; And a skew of the needle roller in a tripod type constant velocity universal joint including a roller accommodated therein, wherein the roller is guided by roller guide surfaces formed on both side walls of the track groove on an outer peripheral surface thereof. By restricting the angle within a predetermined standard value, it is possible to reduce the vibration of the tripod type constant velocity universal joint.

The invention according to claim 4, wherein the smaller of the skew angle (θ1) that can be caused by the circumferential clearance and the skew angle (θ2) that can be caused by the radial clearance is the skew angle that can actually occur. The skew angle (θ1) of the needle rollers that can be caused by the circumferential clearance is changed by the skew angle of the needle rollers that can be caused by the radial clearance in the annular space between the roller and the trunnion journal. By making it larger than (θ2) (θ1> θ2), it is possible to take measures against skew of the needle rollers by restricting only the latter skew angle (θ2) as in the invention of claim 2.

[Brief description of the drawings]

1A is a cross-sectional view of a tripod type constant velocity universal joint, and FIG. 1B is a longitudinal sectional view of a tripod type constant velocity universal joint.

2A is an end view of an outer joint member, FIG. 2B is a cross-sectional view around a trunnion journal, and FIG. 2C is a partially enlarged view of FIG.

FIG. 3 is an explanatory diagram for explaining skew of a needle roller.

FIG. 4 is an enlarged cross-sectional view of a contact portion between a roller and a roller guide surface, where (A) is a case of an angular contact;
(B) shows the case of a circular contact.

FIG. 5 is a graph showing a relationship between a skew angle (θ2) and induced thrust.

FIG. 6 is a cross-sectional view of a tripod-type constant velocity universal joint showing an embodiment of the present invention and a conventional example in a left-right manner.

[Explanation of symbols]

 Reference Signs List 10 outer joint member 12 track groove 14 roller guide surface 16 small inner diameter portion D1 inner diameter 18 large inner diameter portion D2 inner diameter 20 tripod member 22 trunnion journal 24 cylindrical outer peripheral surface 26 ring groove 30 roller do outer diameter Ls width 32 needle roller d Roller diameter l Effective length 34 Outer / washer 34a Disk 34b Cylindrical 34c Large diameter 36 circlip 38 inner washer

Continuing from the front page (72) Inventor Kenji Terada 1578 Higashikaizuka, Iwata City, Shizuoka Prefecture Inside (72) Inventor Hisaaki Kura 1578 Higashikaizuka, Iwata City, Shizuoka Prefecture F Term (in reference) 3J101 AA14 AA24 AA31 AA42 AA52 AA62 AA72 BA54 BA55 BA56 BA77 FA02 FA31 FA53 GA14

Claims (7)

[Claims] 1. An outer joint member having a track groove extending in an axial direction at an inner circumferential position divided into three equal parts in a circumferential direction, a trunnion body fitted to a shaft so as to transmit torque, and a circumference of the trunnion body. A tripod member consisting of a trunnion journal protruding radially from the direction trisection position, and a roller housed in the track groove rotatably mounted on each of the trunnion journals via a plurality of needle rollers. A tripod type constant velocity universal joint in which the roller is guided by roller guide surfaces formed on both side walls of the track groove on the outer peripheral surface thereof, wherein the skew angle of the needle roller is set to a predetermined standard value. A tripod-type constant velocity universal joint characterized by being restricted inside. 2. A skew angle of a needle roller generated by a radial clearance of the needle roller in an annular space between the roller and the trunnion journal is regulated to a predetermined standard value. The tripod type constant velocity universal joint according to claim 1. 3. The skew angle (θ2) is 4.0 ° or more.
The tripod type constant velocity universal joint according to claim 1, wherein the angle is within a range of 4.5 °. 4. A needle roller skew angle (θ1), which may be caused by a circumferential clearance, may be caused by a radial clearance in an annular space between the roller and the trunnion journal. The tripod-type constant velocity universal joint according to any one of claims 1 to 3, wherein the value is larger than (θ2). 5. A contact ratio between the roller and the roller guide surface is set to 1.02 to 1.2, and the contact ellipse generated on the roller does not deviate from an end surface of the roller at a predetermined torque load. 5. The tripod type constant velocity universal joint according to claim 1, wherein a width dimension is reduced. 6. A width (Ls) and an outer diameter (do) of the roller.
6. The tripod type constant velocity universal joint according to claim 5, wherein a value of a ratio (Ls / do) with respect to the range is 0.24 to 0.27. 7. The width dimension of the roller such that the contact surface pressure generated between the roller and the roller guide surface is substantially equal to the contact surface pressure generated between the trunnion journal and the needle roller. The tripod-type constant velocity universal joint according to any one of claims 1 to 6, wherein the length of the needle roller is set.